2018 Mercedes-Benz SL550

The 2018 Mercedes-Benz SL550 is a luxury roadster known for its powerful engine, elegant design, and comfortable ride. Other engine options for this model year include the SL450 with a 3.0L V6 biturbo engine (362 hp and 369 lb-ft of torque) and the SL63 AMG with a 5.5L V8 biturbo engine (577 hp and 664 lb-ft of torque). The SL550 boasts a 4.7L V8 biturbo engine producing 449 hp and 516 lb-ft of torque. Owners often praise its refined interior, smooth handling, and retractable hardtop, offering both open-air enjoyment and coupe-like comfort. Common complaints include the high cost of maintenance and repairs, as well as some issues with the electronic components. All engine options are paired with the Mercedes-Benz 9G-TRONIC 9-speed automatic transmission.

Engine

4.7L V8 Biturbo

• Oil Leaks from Valve Cover Gaskets
  • Description/Symptoms: Oil leaks are observed around the valve cover gaskets. This can lead to a burning smell and low oil levels.
  • Solution: Replacement of the valve cover gaskets.
  • Estimated Cost to Fix: $500 - $1000+
  • Recalls: None Found
• Turbocharger Issues (Wastegate Actuator)
  • Description/Symptoms: Reduced engine power, unusual noises (whining or rattling) from the turbocharger area, and potential error codes related to turbocharger performance.
  • Solution: Replacement of the wastegate actuator or, in more severe cases, the entire turbocharger assembly.
  • Estimated Cost to Fix: $800 - $3000+
  • Recalls: None Found

Transmission

9G-TRONIC 9-Speed Automatic Transmission

• Rough Shifting/Hesitation
  • Description/Symptoms: Harsh or delayed shifting between gears, especially during acceleration or deceleration. Can also exhibit a “clunking” sound during gear changes.
  • Solution: Software update of the transmission control module (TCM). In some cases, valve body replacement may be required.
  • Estimated Cost to Fix: $300 - $2500+
  • Recalls: None Found

Suspension

• AIRMATIC Suspension Problems
  • Description/Symptoms: The AIRMATIC suspension can experience issues such as sagging on one side, complete failure to maintain ride height, or compressor failure. This can result in a very rough ride and impaired handling.
  • Solution: Diagnosis and repair or replacement of faulty components, such as air struts, air compressor, or valve block.
  • Estimated Cost to Fix: $800 - $3000+ per strut, $500 - $1500 for the compressor.
  • Recalls: None Found

Electrical

• COMAND System Malfunctions
  • Description/Symptoms: The COMAND infotainment system can experience freezing, unresponsive touch screen, navigation errors, or Bluetooth connectivity issues.
  • Solution: Software update, system reset, or replacement of the COMAND unit.
  • Estimated Cost to Fix: $300 - $2000+
  • Recalls: None Found
• Battery Drain Issues
  • Description/Symptoms: The car battery drains quickly, especially when the vehicle is not in use for an extended period. This can lead to difficulty starting the car.
  • Solution: Diagnosing the source of the parasitic draw and repairing or replacing the faulty component. Common culprits include the COMAND system, seat control modules, and alarm system.
  • Estimated Cost to Fix: $100 - $1000+
  • Recalls: None Found
• Convertible Top Malfunctions
  • Description/Symptoms: The retractable hardtop mechanism can fail to operate smoothly, get stuck, or display error messages. This can be due to issues with the hydraulic system, sensors, or motors.
  • Solution: Inspection and repair or replacement of faulty components in the convertible top system.
  • Estimated Cost to Fix: $500 - $3000+
  • Recalls: None Found

Exterior

• No Issues Found

Interior

• Seat Heater Malfunctions
  • Description/Symptoms: The seat heaters can fail to work properly, either not heating at all or overheating.
  • Solution: Replacement of the seat heater element or control module.
  • Estimated Cost to Fix: $300 - $800+
  • Recalls: None Found

Summary

The 2018 Mercedes-Benz SL550, while offering a luxurious and powerful driving experience, is prone to certain issues. Engine oil leaks and turbocharger problems with the 4.7L V8, along with transmission shifting issues, are potential concerns. The AIRMATIC suspension and electrical system, particularly the COMAND system and battery drain, also exhibit vulnerabilities. These issues range in severity, with some being relatively minor and inexpensive to fix, while others, such as suspension or turbocharger repairs, can be costly. Potential buyers should be aware of these common problems and factor in the cost of potential repairs when considering this vehicle.